But Viconia made her choice realizing consequences so her mind is definitely more open for changes what you can't say about Minthara.
This is the most frustrating thing about Act 1 Minthara. The relic causes her to regain control of herself and almost instantly she's doing things that she wouldn't be doing while under the Absolute's control. She feels unsettled by that control being gone, but is very quick to readjust to who she really is. But for the sake of not giving her the narratively obvious non-evil recruitment option they've made it so for some godforsaken reason the relic only works on her AFTER you've committed to the evil path or leave the Tieflings to die and rescue her. In Nere's case you aren't even protecting him with the relic, you're just talking him down so it makes the limitations put on Minthara EVEN MORE nonsensical and frustrating.